316 OF THE SAL1V4 AND TEARS SECT. XXfV. 2. 5. 4, 



difFufed over the whole ball, and as the external an- 

 gle of the eye in winking is doled iboner than the 

 internal angle, the tears are gradually driven foi- 

 wards, and downwards from the lacrymal gland to 

 the puncta lacrymalia. 



2. The lacrymal fack, with its puncta lacrymalia, 

 and its nafal duel, is a complete gland ; and is fm- 

 gular in this refpect, that it neither derives its fluid 

 from, nor difgorges it into the circulation. The 

 fimplicity of the ftructure of this gland, and both 

 the extremities of it being on the furfaceof the body, 

 makes it well worthy our minuter obfervation ; as 

 the actions of more intricate and concealed glands 

 may be better underftood from their analogy to this, 



3. This fimple gland confifts of two abforbing 

 mouths^ a belly, and an excretory duel. As the 

 tears are brought to the internal angle of the eye v 

 thefe two mouths drink them up, being ftimula-ted 

 into action by this fluid, which they abforb. The 

 belly of the gland, or lacrymal fack, is thus filled, in 

 which the faline part of the tears is abforbed, and 

 when the other end of the gland, or nafal duel, is 

 ftimulated by the drynefs, or pained by the coldnek 

 of the air, or affected by any acrimonious duft o? 

 vapour in the noftriis, it is excited into action toge- 

 ther with the fack, and the tears are difgorged upon 

 the membrane, which lines the noftriis ; where they 

 ferve a fecond purpofe to moiften, clean, and lubri- 

 cate the organ of fmeil. 



4. Whea- the nafal duet of this gland-is ftimulated 

 by any Very acrid material, as the powder of tobac- 

 co, or volatile fpirits, it not only difgorges the con- 

 tents of its belly or receptacle (the lacrymal fack;, 

 and abforbs haftily all the fluid, that is ready for it 

 in the corner of the eye ; but by the aifociation of its 

 motions with thofe of the lacrymal gland, it excites 

 that alfo into increafed action,- and a large flow of 

 tears is poured into the eye* 



5. Thir 



